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Monday, November 17, 2014

European Space Agency Images Show Philae's Bounce During Landing

Philae touchdown site seen by Rosetta's navigation camera. The first
image in this sequence was taken on 12 November at 15:30 UTC, just
before the lander's first touchdown; the second image was taken at 15:35
UTC, right after touchdown. The large red circle indicates the position
of the shadow of the dust cloud caused by the landing. The third image
in the sequence is the same as the second, with the likely position of
Philae and its shadow highlighted. Credits: ESA/Rosetta/NAVCAM;
pre-processed by Mikel Catania

The
European Space Agency released images of the Philae probe's bounce that occurred during its soft-landing on Comet
67P/Churyumov–Gerasimenko last week.

Philae bounced twice after its first touchdown on the near-gravitation-less comet. The
first bounce was about 1 kilometer above the comet's surface and
downrange from the designated landing site. A second, lesser bounce
occurred, again
sending it airborne. Philae then came to an uncontrolled rest on the
comet with at least one landing foot pointing outward rather than down
towards the comet's surface. The bounce was caused by the failure of the probe's two harpoons
to fire and reel the spacecraft into a proper landing position on the
comet's surface.

Rosetta’s lander Philae is safely on the surface of Comet
67P/Churyumov-Gerasimenko, as these first two CIVA images confirm. One
of the lander’s three feet can be seen in the foreground. The image is a
two-image mosaic. Credit: ESA

After the comet landing, the Philae went into hibernation
because its solar panels are not in the correct angle to be
adequately charged by the Sun's rays. However,
ESA scientists were able to command the lander to lift its body by
about 4 centimeters and rotate about 35 degrees in an attempt to receive
more solar energy to help mitigate these landing misfortunes. But as
the last science data fed back to Earth, Philae’s power rapidly
depleted, ESA reported.
For the remainder of the mission, no contact will be possible with
Philae unless sufficient sunlight falls on its solar panels to generate
enough power to wake it up.

Before
Philae went into hibernation, Rosetta, the spacecraft orbiting the
comet and acting as a communications relay from Philae to Earth, was
able to re-established contact with the probe for about two hours on
Friday. This communication was long enough time for the probe to
transmit its housekeeping and science date back to Earth.

The
Rosetta mission was launched over a decade ago from Europe’s spaceport
in Kourou, French Guiana. During this long voyage, Rosetta had to make
three gravitational sling shot maneuvers around the Earth and one
around Mars to gain enough speed to catch up with Comet 67P/
Churyumov-Gerasimenko.

Rosetta
neared the icy comet on August 6, 2014. After several months of
maneuvering the spacecraft into a precise orbit around the comet,
Rosetta launched its Philae probe on Wednesday at 4:03 a.m. Eastern
Standard Time (09:03 GMT).

Rosetta
is the first mission ever to orbit a comet’s nucleus and soft-land a
probe on its surface. Rosetta will also be the first spacecraft to fly
alongside a comet as it heads towards the inner Solar System, observing
how a frozen comet is transformed by the warmth of the Sun. By studying
the nature of the comet’s dust and gas, scientists hope that the
Rosetta mission will help them understand more about the role of comets
in the evolution of the Solar System.